How do you connect? If you aren't actively and intelligently taking precautions, they may well have enough network address history to be fairly definitive.
Also, do you block their widgets on other sites/pages?
Not that I disagree with the "Big Brother" concerns that this "Ihre Papiere, bitte." activity raises.
P.S. Aside from government(s), of what value is a proven identity to commercial interests? Being able to prove that you/they are targeting exactly who they want.
Hmm... Amongst other things, I understand that process servers are already attemtping to use FB as a accepted means of delivery. And I've read that debt collectors are using accounts having profile pictures of bikini clad young women, in order to successfully "friend" those they wish to hound.
All sorts of value to "proven" identities...
